A couple of notes.
1.) You may have a hard time getting all of your equipment in an Air 540. It's possible to do but it may require a bit of customization. The board takes up more space than one thinks.
2.) It seems easier to buy the Natex config with the memory as well. I believe others have tried to price it out separately and unless you find a screaming deal you're better off getting it in a package.
http://www.natex.us/product-p/intel-s2600cp2j-128gb-nanya.htm
3.) Heatsinks from Natex won't be enough to run it with any load for too long. You can pickup whichever 2011 cooler you think works. I ran mine for a while on Hyper 212 coolers and they worked well. You'll also have to experiment with the cooling options built in to the system as it can be somewhat picky when you don't run it in one of the Intel P4000 cases.